The present invention relates to an ion laser apparatus and, more particularly, to an ion laser apparatus having an improved cooling structure for a laser capillary.
As conventional methods of cooling an ion laser apparatus, an air cooling method and a water cooling method are known.
FIG. 3 shows a conventional air-cooled ion laser apparatus, and FIG. 4 shows a conventional water-cooled ion laser apparatus.
In FIGS. 3 and 4, reference numeral 1 denotes a laser capillary consisting of BeO. A discharge path 2 is formed at the center of the laser capillary 1, a feedback path 3 for a laser medium such as an argon gas is formed around the laser capillary 1, and a metallized layer 4 is formed on the outer surface of the laser capillary 1. Reference numerals 5a and 5b denote a pair of laser mirrors; 6, a hot cathode arranged in a cathode bulb 7 consisting of stainless; 8, an anode; 9 (FIG. 3), heat radiation fins brazed on the laser capillary 1 by the metallized layer 4; and 10, a pipe, having cooling water inlet and outlet ports 11 and 12 and brazed on the laser capillary by the metallized layer 4, for causing cooling water to flow around the laser capillary 1.
In a laser apparatus using the laser tube shown in FIG. 3, an air cooling fan (not shown) for cooling the heat radiation fins is used. In addition, when a water cooling method is used, a cooling unit (not shown) for cooling water and a cooling water circulating system (not shown) are required.
In the above conventional air-cooled ion laser apparatus, hot air is blown by causing the air cooling fan to cool the cooling fins, and the hot air cannot be easily handled depending on applications of the ion laser apparatus. Since the vibration of the air cooling fan is transmitted to the laser apparatus to vibrate the laser tube, the position of the laser beam emitted from the laser apparatus is vibrated in synchronization with the vibration of the laser apparatus. In addition, unlike in the air cooling method, although a water cooling method does not have the above problems, i.e., the handling of hot air and the vibration of the fan, the water cooling method has the following drawback. That is, the water cooling method requires a cooling unit for cooling water and a cooling water circulating system, thereby increasing the size of the water cooling unit.
As described above, since the conventional air- and water-cooled ion laser apparatuses have advantageous and drawbacks, they are selectively used according to their application purposes. However, in experiments or the like, since two ion laser apparatuses, i.e., air- and water-cooled ion laser apparatuses must be prepared, a large investment in equipment is required.
In addition, two types, i.e., air- and water-cooled laser apparatuses must be manufactured in manufacturers, and both the types of lasers are expensive.
In order to solve the above problems, as disclosed in Japanese Patent Laid-Open No. 58-213486, the following ion laser tube is proposed. In the laser ion laser tube, after heat generated by a laser capillary is temporarily absorbed in a cooling liquid in a pipe, the heat absorbed in the cooling liquid is radiated through heat radiation fins arranged on the outer peripheral portion of the pipe. However, since the laser capillary is cooled with air through the cooling liquid, a high cooling efficiency cannot be obtained. In addition, a water cooling method or an air cooling method cannot independently used.